1. Field of the Invention
The present invention relates to a surge energy transfer circuit related to surge suppression techniques, and more particularly to an integrated circuit that can not only absorb surge energy but also convert the remaining surge energy into usable voltage form that also completely protects power facilities.
2. Description of the Related Art
Surge vulnerability interference arises from the large energies involved, making it a major source of surge interference. Lighting flash surge (LFS) is a typical source of surge interference. As a practical matter, power facilities are prone to failure when confronted with LFS due to insufficient surge protection.
As for adequate surge protection schemes used for securing normal operations of power facilities, many patents have been disclosed, such as U.S. Pat. No. 5,353,189 “Surge protector for vehicular traffic monitoring equipment”, U.S. Pat. No. 5,617,284 “Power surge protection apparatus and method”, U.S. Pat. No. 5,038,245 “Method and apparatus for suppressing electrical transients”, U.S. Pat. No. 4,677,518 “Transient voltage surge suppressor”, U.S. Pat. No. 4,584,622 “Transient voltage surge suppressor”, and the like. All of these patents basically employ a structure that emphasizes on the use of a clamping voltage or remnant surge voltage suppression while lacking an adequate consideration of processing surge energy.
Remnant surge voltage is not the main cause leading to power facility failures. Remnant surge energy generated by a residual current flowing in the power equipment must be taken into account as well. According to ANSI/IEEE C62.41 standard “Recommended Practice on Characterization of Surges in Low-Voltage (1000 V and Less) AC Power Circuits”, outdoor power facilities are classified as C category devices for surge interference. A combination waveform surge test in accordance with the C3 category is 20 kV 1.2/50 μSec and 10 kA 8/20 μSec. The energy generated by the combination waveform surge can go up to more than 1,000 Joules and easily destroy power facilities.
The reason that methods of the prior art are ineffective in processing surge energy lies in using circuits built around a surge protection device, a gas tube choke, to process the surge and targeted at reducing the remnant surge voltage of the power supply end of power facilities. However, as the current withstanding capability of the choke is low, there are no methods explaining how to reduce the remnant surge energy of the power supply end of power facilities. In fact, methods or techniques for reducing remnant surge voltage fail to effectively process surge energy, with the result that surge energy may still easily destroy power equipment.
To overcome the shortcomings of the prior, the inventor has disclosed an effective alternative in US Patent Application No. 2009/0109585 A1, entitled “Series surge suppression structure”, that is, a method that takes the clamping voltage and energy storage into account, to significantly reduce remnant surge voltage and remnant energy entering power facilities, thereby achieving a superior protection result.
In pursuit of constant betterment, a surge energy transfer circuit is further developed to absorb and transfer surge energy by means of a parameter adjustment design, significantly lowering the surge energy entering power facilities and reducing remnant surge voltages, and ensuring to substantially protect power facilities and enhance surge immunity within power facilities.